Why should you reproduce independently low frequencies?
Practical and qualitative reasons are given for explanation:

• The space and volume of classical speakers are inevitably limited, hence the impossibility to use speakers taht would be big enough to reproduce low frequencies.
• Since the low frequencies are not directive, they are not involve in the stereo effect. Therefore, a single source of low frequency is enough and you can place it wherever you want.
• As you know: a car is equipped of a trunk, which appears as the perfect place for your speakers

Specific Speakers
Since low frequencies are reproduced with a specific speaker, models that are specially adapted to the lowest frequencies are available. Therefore, the diameter is bigger: 10, 12, or 15 inches. Equipped with a big magnet and a chassis, its power combines its efficiency with its response in low frequencies. Oxygen Audio thus offers various models, with different diameters, in different lines so to meet every need, including the SPL competition where only the sound pressure matters.

Specific Subwoofers Boxes
To work properly, a Subwoofer must be installed in a Subwoofer box adapted to its electrical and acoustic characteristics. Different types of charges are possible: closed charge, bass-reflex charge (decompression and accord air vent), and band pass (indirect emission of air vent accord). In any cases, the whole volume of the Subwoofer box must be precisely calculated. All our subwoofers are delivered with all the necessary indications for an optimal use, often following several principles.

Specific Amplification
Reproducing low frequencies require much more energy, that is to say power, than medium and high frequencies (estimated to 70% for low frequencies and 30% for the rest of the band). That is why the use of an independent power amplifier is essential, not to say an obligation. Assembling a stereo amplifier into a Bridge circuit is here very important. Even better, monaural amplifiers that are specially designed for the reproducing of low frequencies are now available. They function along the digital technology, which is known as the Digital Class at Oxygen Audio: a very high and superior power is supplied without creating an excessive heat.

Filtering
To bring the functioning of the Subwoofer to perfection, it is essential that it only receives the frequencies it is supposed to reproduce. This is what the low-pass filter, integrated in our amplifiers, controls. It permits to choose with precision the cut frequency below which the Subwoofer box will start working, and whatever the configuration of each installation, that can anyway be adapted to one’s tastes and needs.

Specific Cases
Please take note that on certain source units, outputs reserved to the Subwoofer are available: they enable you to choose directly on the source unit the sound level of low frequencies. Last but not least, Oxygen Audio offers ready-to serve subwoofers boxes, with active or passive speakers.